Chris, I don't know about the 1V or the 2X converter but I use a set of "Kenko" extension tubes with my 100-400IS USM on an A2 body. The set of 3 tubes was bought new for just over $100.00 US if I remember right. The set is made up of a 36mm, 20mm and 12mm tubes AF is retained but at a slight lose of speed. Still accurate focusing though.
Hope this helps Tom * **** ******* *********************************************************** * For list instructions, including unsubscribe, see: * http://www.a1.nl/phomepag/markerink/eos_list.htm ***********************************************************
